Aluminum alloy has been widely used due to its excellent workability, and double-pulse metal inert gas welding (MIG) has become a popular technique in aluminum alloy welding. In this study, a cross-complementary test was performed to study the effect of double-pulse characteristics on weld bead formation and mechanical properties in MIG welding. The test was carried out on an AA6061 aluminum alloy using flat overlaying welding. After welding, the micro-metallographic structure and macro-mechanical performance of the weld bead were explored. The test results showed that the two methods of increasing the base current amplitude or the low-frequency of the current effectively enhanced the oscillation of the molten pool, refined the grain size of the fusion zone, and improved the mechanical properties of the weld. Additionally, by comparing the macroscopic photograph of the specimen and the corresponding welding parameters in the test, the formation characteristics of the bead’s fish-scale pattern in double-pulse MIG welding were found when appropriate welding parameters were adopted and weld bead formation was good. This test result provides a strong scientific basis for the selection of welding parameters in the actual promotion and application of double-pulse MIG welding.

中文翻译：

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双脉冲特性对金属惰性气体焊接中焊道形成和力学性能的影响

铝合金因其优异的加工性能而得到广泛应用，双脉冲金属惰性气体保护焊（MIG）已成为铝合金焊接中的流行技术。在这项研究中，进行了交叉互补测试以研究双脉冲特性对 MIG 焊接中焊道形成和机械性能的影响。该测试是在 AA6061 铝合金上使用平堆焊进行的。焊接后，对焊道的微观金相组织和宏观力学性能进行了探索。试验结果表明，增大基极电流幅值或电流低频两种方法有效地增强了熔池的振荡，细化了熔合区的晶粒，改善了焊缝的力学性能。此外，通过试样宏观照片与试验中相应焊接参数的对比，发现采用合适的焊接参数且焊道成形良好时，双脉冲MIG焊接中焊道鱼鳞纹的形成特征。该试验结果为双脉冲MIG焊接实际推广应用中焊接参数的选择提供了强有力的科学依据。